Sonos Amp With Older Bose Acoustimass 5 Series Lacking Bass

Can you supply a ink to these speakers, so that we can look at the connections that are available on them? The issue isn't likely to be with the Sonos, but instead either with the way it is connected to the BOSE equipment, or the BOSE equipment itself.

Bose Acoustimass 5 Series II

https://assets.bose.com/content/dam/Bose_DAM/Web/consumer_electronics/global/products/speakers/am5_series2/pdf/owg_en_am5_series2.pdf

I've played with it most of the day. Different music sources, different placement of the Bose, different volumes, switching back and forth between the Sonos Amp and my original Harmon Kardon amp; and the bass is definitely missing it's normal levels. On the brighter side of things, it seems the music playing through Sonos Amp (CD or turntable) to the Play 5 speakers elsewhere in the house sound the same as music that is streaming from iTunes or iHeart Radio. So there's that for $600.

Thanks for that link. I'd say it was helpful, except I can't find any data on the inputs to the device. How/where do you connect the Sonos Amp to that?

The Sonos Amp would be putting out the same kind of signal as your Harmon Kardon amp, across all frequencies, so I'm a bit confused. Unless you've plugged something in to the Sonos Amp's subwoofer output.

The Bose bass reflex box connects via standard speaker cable to the speaker connections on the Sonos Amp. No real tricky complications with the connections. The two sets of tweeter speakers on the Bose run from the bass box. They sound crystal clear as usual. There is a diagram of the connections in that link I gave.

I'd check that you don't have one pair of Amp to box speaker cables swapped in polarity.

Amp changes of these kind do not have the effect you describe unless one of them is wrongly wired, has its EQ not set to a similar position as the other, or is defective.

So to update, and allow myself to be flamed a little. After the last couple of weeks listening to my "bass-less" Bose speakers, I decided to move things around yet again. Completely disconnecting all speaker wires to relocate things. Upon reconnecting the Bose bass reflex box, I saw it. The words "Output - To Cube Speakers" where I had the main speaker wire from the Sonos Amp connected in the past. They should be connected to "Inputs - From Amp or Receiver". Even before, when my Harmon Kardon was connected, the main speaker wire was connected incorrectly!! Who knows how long I had listened to sub par music? And it's just as odd to me that the speakers would even work that way! Then the final twist in the mystery, the Bose speakers did indeed sound better hooked up incorrectly to the HK than when hooked up incorrectly to the Sonos. Not that this matters whatsoever, but still.

Thanks for indulging me with my stupid discovery. Music sounds GREAT again!